Question

A pipe that is closed at one end can be made to resonate by a tuning fork at a length
of 0. 25 m. The next resonant length is 0. 75 m. Speed of sound is 338 m/s.
(a) Calculate the wavelength of the sound emitted by the tuning fork;
(b) Calculate the frequency of the tuning fork.

Answer 1

closed end pipe
lowest res when node at closed end, antinode at open so
1/4 wavelength = 0.25 m
next time node at wall and antinode at open end is when
3/4 wavelength = 0.75 m
well, that works, 3 times .25 is .75 :)
so if L is wavelength
(1/4 ) L = .25 = 1/4
looks like L = 1 meter
it goes one meter in one period T
so 338 T = 1 meter
T = 1/338 seconds
f = 1/T =338 Hertz